Systems for the simulation of vehicle operation are well known. Among these systems are vehicle operating simulators, which can be operated by a driver manipulating conventional controls and producing visual, aural and tactile feedback, such as those taught by Briggs, et al, in U.S. Pat. No. 4,952,152 and DeGroat, et al, U.S. Pat. No. 5,277,584.
Systems for the analysis of the forces imposed on a motor vehicle during operation are also well known. Using traditional finite element analysis (FEA) techniques, it is possible to construct so-called FEA models of vehicles and their component parts utilizing a computer, and further, to use the computer to simulate forces acting upon the vehicle computer model to determine and predict stress, strain, durability and fatigue of vehicle components.
Our own finite element model builder system is an example of the current state of the art in the creation of finite element models using finite element analysis. With these systems, the structure of a motor vehicle body, chassis, drive train, suspension and other component parts can be created as a computer model. Manipulation of this model can then be performed in a variety of ways to assist the vehicle designer. The model can be viewed on a typical video display device, which allows the designer and engineer to rotate the view of the model, manipulate the components of the model and test the results of said manipulation or modification of the model.
Our software also interfaces with a wide variety of other computer programs, for example, computer programs which assist in the designing of production tools.
It is also known to utilize FEA models in a dynamic simulation environment. For example, a motor vehicle suspension model can be subjected to a repetitive computer-simulated force comparable to that force imposed on an actual motor vehicle suspension, e.g., the vehicle's encounter with a roadway pothole. By repeating this simulation, repetitive stresses on suspension components can be effectively evaluated, without the need to actually subject the physical component to the physical roadway conditions, in a much shorter time at less expense than that required by actual operation of a vehicle in the proving ground environment.
An underlying problem with prior simulation methods and systems is the imprecision of the inherent estimations which are required to run the simulations. For example, in prior art "pothole" simulations, the systems assumed that the forces transmitted by the impact of the motor vehicle tire with a pothole would result in an isolated vertical force being applied to the vehicle's suspension and body. In reality, the pothole also results in a rearward force on the vehicle's suspension when the vehicle tire strikes the vertical surface of the pothole as the vehicle travels forward. Further, prior simulation techniques largely ignored the size, shape, mass, geometry and dynamics of the wheel/tire combination, and treated forces applied to the motor vehicle suspension and vehicle body as essentially point source forces at particular points in the vehicle suspension. Such assumptions have been shown to provide largely inaccurate simulation data.
The present invention allows for the modeling and simulation of all vehicle components in the proving ground environment. Previous systems have been limited to the simulation of various vehicle sub-systems, but not the vehicle as a whole. The present invention also provides better consistency between successive tests and better consistency within specific model configurations. By providing an accurate model of both the vehicle and the road surface, any change in the individual model elements (e.g., the tire model) will isolate the effects of substitution of different elements under consideration, provided all other vehicle components and models remain unchanged.